root@generate-random:~/jwt-tokens/javascript$ _

Generate JWT Tokens in JavaScript

Complete code tutorial with examples and best practices

PHP

JavaScript

[ Code Example - Quick Summary ]

Language: JavaScript

What: Generate secure JWT tokens in JavaScript using the jsonwebtoken library for Node.js. Perfect for Express.js APIs, authentication middleware, and stateless session management.

Try it: Use our interactive Jwt-tokens generator or integrate this code into your JavaScript application.

Generate secure JWT tokens in JavaScript using the jsonwebtoken library for Node.js. Perfect for Express.js APIs, authentication middleware, and stateless session management. Looking for other languages? Check our code examples in PHP , Python , Java , C# , C++ , Ruby and Go or use our interactive web generator.

JavaScript Code Example

const jwt = require('jsonwebtoken');

// Secret key (store in environment variables)
const SECRET_KEY = process.env.JWT_SECRET || 'your-256-bit-secret-key';
const ISSUER = 'https://yourdomain.com';
const AUDIENCE = 'https://yourdomain.com';

// Create token payload
const payload = {
    user_id: 123,
    username: 'john_doe',
    role: 'admin'
};

// Generate JWT with options
const token = jwt.sign(payload, SECRET_KEY, {
    algorithm: 'HS256',
    expiresIn: '1h',        // 1 hour
    issuer: ISSUER,
    audience: AUDIENCE
});

console.log(token);
// Output: "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyX2lkIjoxMjMsInVzZXJuYW1lIjoiam9obl9kb2UiLCJyb2xlIjoiYWRtaW4iLCJpYXQiOjE2ODAwMDAwMDAsImV4cCI6MTY4MDAwMzYwMCwiaXNzIjoiaHR0cHM6Ly95b3VyZG9tYWluLmNvbSIsImF1ZCI6Imh0dHBzOi8veW91cmRvbWFpbi5jb20ifQ.signature"

// Verify and decode JWT
try {
    const decoded = jwt.verify(token, SECRET_KEY, {
        issuer: ISSUER,
        audience: AUDIENCE
    });
    console.log(decoded);
} catch (err) {
    console.error('Invalid token:', err.message);
}

// Express.js middleware example
const authenticateJWT = (req, res, next) => {
    const token = req.headers.authorization?.split(' ')[1]; // Bearer token

    if (!token) {
        return res.sendStatus(401);
    }

    jwt.verify(token, SECRET_KEY, (err, user) => {
        if (err) return res.sendStatus(403);
        req.user = user;
        next();
    });
};

[EXPLANATION]

The jsonwebtoken library is the most popular JWT implementation for Node.js. It supports both symmetric (HS256) and asymmetric (RS256, ES256) algorithms. The sign() method creates tokens, while verify() validates them. Use environment variables for secret keys and implement proper error handling for token validation.

Expected Output

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VyX2lkIjoxMjMsInVzZXJuYW1lIjoiam9obl9kb2UiLCJyb2xlIjoiYWRtaW4iLCJpYXQiOjE2ODAwMDAwMDAsImV4cCI6MTY4MDAwMzYwMCwiaXNzIjoiaHR0cHM6Ly95b3VyZG9tYWluLmNvbSIsImF1ZCI6Imh0dHBzOi8veW91cmRvbWFpbi5jb20ifQ.YVPuJ_EqJr8vOT5JkUqHxX9Rj3LmN4K8sQ2TpY6wZ1c